SOCIAL-ISOLATION INCREASES CHOLECYSTOKININ MESSENGER-RNA IN THE CENTRAL-NERVOUS-SYSTEM OF RATS

To investigate cholecystokinin (CCK) mRNA changes induced by social is olation rats were isolated in single cages soon after weaning for 30 d ays. They were then sacrificed and their brains removed for in situ hy bridization (ISH) study. Control animals were housed in groups of 6 pe r cage for the same period. ISH was performed using a P-32-labelled ol igonucleotide probe complementary to CCK-8 mRNA and the results analys ed by computerized densitometry. They showed a significant increase (f rom 59.5-152.3%) in CCK mRNA expression in the basolateral amygdala, c ortex, CA1, dorsal raphe nucleus, geniculate body and ventral tegmenta l area of isolated rats. These results suggest that social isolation m ay influence CCK gene expression.